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UNITED STATES PATENT OFFICE.

.IIE()RGIC F. HUTCHINS, OF \VORCE. TER, MASSACHUSETTS, ASSIGNOR TO THEKNOIVLES LOOM \VORKS, OF SAME PLACE.

LET-OFF MECHANISM FOR LOOMS.

SPECIFICATION forming part of Letters Patent No. 417,033, dated December10, 1889.

Application filed September 23, 1889. Serial No. 324,845. (No model.)

To all whom it may concern.-

Be it known that I, GEORGE F. HUTCHINS, a citizen of the United States,residing at Vt orcester, in the county of lVorcester and State ofMassachusetts, have invented certain new and useful Improvements inLet-0ft Mechanism for Looms; and I do hereby declare that the followingis a full, clear, and exact description thereof, which, in connectionwith the drawings making a part of this specification, will enableothers skilled in the art to which my invention belongs to make and usethe same.

My invention relates more particularly to a let-oft mechanism for ribbonor tape looms in which the head of the warp-beam is grooved to receive afriction-band.

The object of my invention is to provide a let-oft which shall beautomatic in its operation; and my invention consists in certain novelfeatures of construction of a let-off mechanism, as will be hereinafterfully described, and the nature thereof indicated in the claims.

Referring to the drawings, Figure 1. is a side elevation of a let-oftembodying my improvements. Fig. 2 is a plan view of the same. Fig. 3 isa side elevation of a modification of my improvements; and Figs. st and0 5 are detail views.

In the accompanying drawings, 1 represents the warp-beam stand, in whichthe warp beam 2 rests.

I 3 is afriction'band, having an eye a at one end, through which passesthe hook 5, fast in the lug 6. There is a similar eye 7 in the other endof the friction band 3, through which passes the hook 8. Thehook 8 has ascrew-thread out upon its shank, and the friction-band 3 is drawn tightover the head 9 of the beam 2 by the pressure of the nut 10 against thelug 11 of the stand ,1, through which the hook 8 passes. The lug 6is onthe doubled-arn1 lever 12, pivot-ed at 13 to the beam-stand 1, and thefriction-band 3 is of such a length as to hold the lever 12 in ahorizontal position. The outer ends of the lever 12 have a recess toreceive the glass rod 14, which is held in place by the cap 15 and screw16. A doubled-arm lever 17 is pivoted at 18 to the lever 12 and carriesa glass rod 20, held in place by the cap 21 and screw 22, the bar 23,connecting the outer ends of the lever 17, being used to hold theweights 24.

The operation of the let-off is as follows: Suppose the lever 17 to bein the position indicated by the dotted lines, Fig. 1, the warp beingrepresented by the heavy dotted lines 25. Then the weight 2% acts on thelever 12 by reason of the warp-threads 25 passing over the glass rod 14and under the glass rod 20, and thus the friction-band 3 is tightenedover the beam-head 9, the resulting friction preventing any rotation ofthe beam, and consequently any let-off of the warp. As the loom weavesand the cloth is taken up, the warp is drawn in the direction of thearrow, Fig. 1, and the lever 17 is moved upward to its position, asshown in the full lines. The part 26 of the lever 12 is a tie connectingthe two sides of the lever, and when. the lever 17 touches this tie 26the two parts 12 and 17 act as one solid lever, and since the warppasses under the glass rod 20 the whole lever is raised upward, thusslacking the frictionband-3 and allowing the beam to revolve un der thetension of the warp-threads 25. As soon as the beam revolves theadditional length of warp thus obtained causes a slackness, which isimmediately taken up by the action of gravity on the weight 24:, and thedownward motion of the lever 17 separates it from the lever 12 and againbrings the pressure of the weight 24 upon the friction-band 3, stoppingany further rotation of the beam. 8 5 The lever 17 would be in sameposition as shown in the dotted lines whenever there had been a pick-outor a slackness for any other cause. It would be in the position as shownin the full lines when the loom was 0 running, and the automaticoperation of letting off the warp, as described above, would be going oncontinually and almost imper ceptibly.

In the modification shown in Fig. 3 the oporation is the same, thedifference in construction being the substitution of the porcelain bars27 and 28 for the glass rods 14 and 20.

The projections 29, Figs. 4 and 5,011 the loo porcelain bars are toprevent the warp-threads from slipping elf sidewise, while the caps 15and the projections 30 on the lever 17, Figs. 1 and 2, answer the samepurpose when the glass rods are used.

The advantages of glass rods or porcelain bars in the levers 12 and 17over any kind of rolls or pulleys are a great reduction of slidingfriction 011 the warp-threads and economy of production; also, when apulley is used, if

, one of the delicate Warp-threads break near the pulley, the thread ifnot at once detected Will Wind round the pulley, making a snarl andoftentimes a bad break.

Having thus described my invention, What I claim as new, and desire tosecure by Letters Patent, is

In a let-off mechanism for looms, the combination, With a Warp-beam andhead and a friction band, of two levers jointed together and pivoted atone end, each lever carrying a glass rod or porcelain bar, and a Weighton the outer lever for the purpose stated, substantially as set forth.

GEORGE F. HU Cl'llNS.

\Vitnesses:

JOHN G. DEWEY, v GEORGE S. DEWEY.

